问题描述: 28×5+2×3×35+21×20+14×40+8×62 55×66+66×77+77×88+88×99脱式计算 1个回答 分类:数学 2014-11-06 问题解答: 我来补答 28×5+2×4×35+21×20+14×40+8×62 =2×2×7×5+2×4×5×7+3×7×4×5+2×7×5×2×4+8×62=2×2×7×5×(1+2+3+4)+496 =10×14×10+496 =1400+496 =1896 55×66+66×77+77×88+88×99=11×5×11×6+11×6×11×7+11×7×11×8+11×8×11×9=11×11×(5×6+6×7+7×8+8×9)=121×(30+42+56+72)=121×200=24200 展开全文阅读